Automated in-game tournaments.

Back in the day, some games used to have their own automated tournaments. Warcraft 3 had very often popping one (I think closer to daily) with some unique rewards, but the game that nobody else has copied, Bloodline Champions, had the best system out of them all.

I really hope they would attempt to copy the system BLC had as it didn't run that often and had different brackets for 3 different set of ranks (or so I remember). Rewards scaled as such that you wanted to compete in higher ones as their currency was a lot more valuable and allowed you to also buy the lower rank stuff.

So basically they started gathering sing-ups in-game a good deal before the matches and had the teams automatically seeded into brackets.
FF might need somekind of option for open teams to allow more participants to join if making pre-mades gets too intimidating and rough.
Having the rewards eventually grindable just by playing in your brackets would be good, the better players would just get their hands faster into them.
Maybe have something unique for high finish, like the current season does frames and such, not something like mounts that will cause extra salt, but little something people would enjoy.

They could utilize the current shops in wolves' den pier to deal out the rewards. In BLC you could buy rank appropriate titles, icons, frames and such so it would probably be very copyable.

I think having them run weekly or so (or maybe twice with only 1 application to play in case people can't make the first day) would make the sparse enough to encourage people to join and not turn it into a daily grind.